The present invention relates to an electronic timepiece.
In the related art, there are known electronic timepieces, each of which has a plurality of motors such as stepping motors, and an antenna for receiving a standard radio wave which is a long radio wave, and performs various operations, such as time correction based on the standard radio wave.
If the operation accuracy of the motors is regarded as important, it is preferable to dispose antimagnetic plates for magnetically shielding the motors from external magnetic fields which may exert influence on the operations of the motors.
However, the antimagnetic plates are made of a material having high relative-permeability, and if such members having high relative-permeability are disposed near the antenna, it becomes easier for eddy current to occur, and loss of electric energy (eddy-current loss) occurs, whereby the receiving sensitivity of the antenna decreases.
For this reason, for example, in Japanese Patent Application Laid-Open No. 2014-062852, it is proposed a technology in which antimagnetic plates for magnetically shielding motors from external magnetic fields are provided and an antenna is disposed so as not to overlap the antimagnetic plates.
However, in a case where an electronic timepiece is a small instrument such as a wristwatch, since every module should be assembled in a limited space of the inside of a case, inevitably, motors and an antenna are disposed close to one another.
In this regard, in the technology disclosed in Japanese Patent Application Laid-Open No. 2014-062852, the antimagnetic plates are formed in different shapes such that the antimagnetic plates do not overlap the antenna while covering the motors.
However, significant manufacturing cost is required in making the antimagnetic plates in different shapes, and the shapes of the antimagnetic plates should be changed depending on the assembly position of the antenna. Therefore, there is a problem that it is impossible to commoditize the antimagnetic plates.
Further, according to the layout of the motors and the antenna, even though the antimagnetic plates have different shapes, it may be difficult to provide sufficient distances between each antimagnetic plate and the antenna, and it may be apprehended that the receiving sensitivity of the antenna will decrease.
In an electronic timepiece which performs time correction on the basis of a standard radio wave, a decrease in the receiving sensitivity of an antenna causes the intrinsic timepiece performance to deteriorate.
For this reason, in electronic timepieces, the antimagnetic properties of motors have been sacrificed to some extent in order to secure the radio-wave reception performance of antennae.